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By Jai Ghosh, Aprad E. Torma, Roger Guay

The catalytic effect of ferrous ion in the industrial biohydrometallurgical heap and dump leaching processes is explained. During the bacterial leaching of metal sulfides, ferric ion will partly be hydrolyzed and a variety of sols, gels, amorphous and/ or crystalline mono- and polynuc- lear hydroxo- and sulfato complex species formed, especially by olation and aggregation reactions. There are many problems associated with these iron precipitates especially in the purification of leach solutions. The present study will discuss the iron precipitation reactions; gives kinetic and thermodynamic evaluations of the effect of temperature on pyrite and ferrous iron oxidation; and reports on the tolerance of heavy metal ion concentrations by Thiobacillus ferrooxidans.

Jan 1, 1989

It is possible to divide industrial minerals into four general categories: 1. fuels, 2. construction materials, 4. agricultural minerals, and 4. industrial minerals. It is proposed to ignore the fuels in the context of this paper and deal in general terms with the others. Mining companies have often considered getting into the industrial mineral business because they can see a resource development with good growth and consistent profits. However, many mining companies being conversant with the metallic side of the industry have spent sleepless nights determining which industrial minerals are most suited for their particular situation. Some have got into the business for the wrong reasons and wished they had never heard of it. Others have successfully adapted to the industrial minerals philosophy and now operate in both metallic and industrial mineral arenas. There is a large difference between firstly, the philosophy and secondly, the functions of being in the industrial minerals business as opposed to metallicÆs. The philosophies can be considered in parallel but it is necessary to clearly have an appreciation of the dominant influences that affect industrial minerals.

Jan 1, 1984

The intention of this paper is to give a review of the present status of lignite mining in the so-called Gulf States in the United States of America, namely Texas, Arkansas, Mis- sissippi and Louisiana. The situation in these states is similar to the situation in Australia in that "Strip Mining - 45 m and Beyond" repre- sents the main technical problem to be over- come in the near future. The solution lies in the application of the bucket wheel excavator.

Jan 1, 1981

By A B. Opperman

For many years explosives energy has been utilized in mining and construction as well as many other applications which are vital to our way of life. Many types of explosives have made their contribution as technology has moved forward. One of the best known was dynamite, which for many years was the mainstay of explosives users. Although dynamite had many advantages over its predecessors, it had the principal shortcomings of being somewhat hazardous to handle and was known as a headache producer.

Jan 1, 1975

The suitability of char from Yallourn brown coal as a filler for carbon electrodes used in the aluminium smelting industry has been assessed on the basis of the specifications usually laid down by electrode manufacturers for petroleum coke fillers. The purity specifications can be met by a simple acid leaching of the coal before carbonization. The true density of char produced at 1200°C is within 5 per cent of the specification figure, but the bulk density of char obtained from as-mined coal is only half that specified for petroleum coke.Although this can be increased to three-quarters of the specified figure by briquetting the coal before carbonization, further increases would be very difficult to achieve, as the remaining shortfall in density is due to an extensive microporosity developed in the particles of char during carbonization.

Jan 1, 1970

By Roberto Maldonado

El presente texto señala el proyecto de profundización en la mina Animón considerando sus características como: geología e hidrogeología, parámetros geomecánicos, niveles de producción, costos de capital y operación, eficiencia del sistema, flexibilidad para cambios en las operaciones, reservas de mineral y consistencia con el sistema de explotación. De forma que a través del conocimiento de estas y de las herramientas gráficas tridimensionales, se pueda analizar las diferentes alternativas, incluyendo condiciones que debe cumplir el proyecto de profundización, el cual abarca también los servicios auxiliares y ventilación.

Sep 12, 2005

By D. Harker, E. Epremian

The constitution of the nickel-tungsten system has been studied by a number of investigators, the most recent of which are Ellinger and Sykes.1 On the basis of metallography, electrical resistivity and hardness measurements and some X ray diffraction work, they constructed a consitution diagram (Fig 1). Ellinger and Sykes report a0 for the alpha face-centered cubic phase (nickel saturated with tungsten) as 3.66?.‡ The gamma phase (tungsten saturated with nickel) is given as body-centered cubic, but no value of a. is recorded. At 43 pct tungsten by weight (approximately 20 at. pct) a beta phase is reported, but structure and lattice parameter are not known. Primarily on the basis of metallographic evidence, they conclude that beta is a new phase and rule out the possibility of formation of a superlattice since they- observe a new phase in the microstructure. Grube and Schlecht2 report an ordering reaction in a system similar to the Ni-W (Ni-Mo) and Harker3 has shown that NirMo forms a superlattice upon the pre-existing face-centered cubic lattice of the alpha phase. Elliniger arid Sykes observed a change in the diffraction pattern of a 4.3 pct W alloy upon aging and attributed it to the formation of a new phase. Thus, there appears to be some question as to the character of the beta phase reported by Ellinger and Sykes. The purpose of the present work is to determine precisely the structure and nature of the beta phase in the Ni-w system of X ray diffraction methods. Experimental Procedure One inch diameter ingots of 43.66 pct, 40.15 pct and 34.06 pct .tungsten by weight (19.8, 17.6 and 14.1 at. pct respectively) were melted and cast under vacuum from electrolytic nickel and pure wire filament grade tungsten. The ingots were soaked for 16 hr at 1300°C in a hydrogen atmosphere furnace, then swaged at this temperature and finally drawn to 0.020 in. diam wire. Some of the bar stock was retained in 1/2 in. diam rod for hardness and metallographic studies. Wire samples for diffraction work were sealed in evacuated quartz tubes and subjected to the various solution and aging heat treatments in a hydrogen furnace. X ray photograms were taken in a Debeye-Slierrer camera using copper K radiation filtered by nickel foil. Results X RAY DIFFRACTION The lattice parameters of the alpha and gamma phases at saturation were determined by an X ray photogram of the 19.8 at. pct W alloy after solution heat treatment at a temperature well within the alpha-gamma range above the peritectoid temperature (17 hr at 1150°C—oil quenched). The alpha phase was found to be face-centeted cubic with a. of 3.594 ± 0.001?, while the gamma phase was determined as body-centered cubic with a. of 3.158 ± 0.001?. Exactly the same phases and parameters were ohtained with the 17.6 at. pct W alloy for the same solution heat treatment. Thorough analysis was made of an X ray photogram of a 19.8 at. pct alloy sample in the quenched and aged condition (solution treated 1T hr at

Jan 1, 1950

By J. L. Viljoen

t has long been the drive of the industry and all operations to create an environment that is free of injury and illness. We have come a long way; the leaders, executives, managers, supervisors and workers are to be commended for relentlessly driving to create, what I call a ?White Flag Day Every Day?. Yet I am also aware of the huge shift we still need to create in the industry, on the operations and in the workplaces to have them free of injury and illness. Keywords People, values, care, trust, belief.

Jan 1, 2011

By Theo Lehner

"The Boliden Rönnskär Smelter operates in the European Context of tight EH&S limits, with ever increasing regulations and tribulations. The near future promises to bring new burdens in the form of C02 trading, miners and pre-treaters increased appetite for a larger share of contained values, and changing compositions and competition in raw materials. On the other hand, European Smelters such as Rönnskär, Harjavalta have demonstrated an astonishing power of survival. This presentation lists and comments on current challenges but opportunities for increased survival power are also presented. One example of the latter is the ongoing investment into increased treatment capacity for e-scrap.UPDATE ON RÖNNSKÄR OPERATIONSThe Rönnskär Smelter has achieved 80 years of age with no signs of retirement. The smelter is most active in spite of its age! And it has undergone some face lift operations to maintain its attractiveness.Raw material, processing facilities and a market for the products are some essential prerequisites for a viable operation. To justify long term survival, economic terms such as return on investments and positive cash flow need to be considered. Below, we illustrate how the Rönnskär Smelter complies with these terms. To update the reader on current operations, our current flow sheet is depicted in Figure 1. The figure summarizes our current input and output."

Jan 1, 2012

By Gary P. Marshall, Jeffery S. Thompson, Robert E. Jenkins

The effectiveness of the new DuPont Passivation Technology in eliminating acid generation from iron sulfides is presented. Passivation is achieved by treatment with a dilute basic perman­ganate solution. This treatment produces a thin impervious layer of iron/manganese oxide on the sulfide surface, providing a bar­rier to the environment so that the sulfide is not available for undesirable reactions such as the production of acid.

Jan 1, 1998

By Harry C. Oussoren, James C. Miles

A new seven kilometer long subway line is being constructed through dense glacial soils under a major thoroughfare in Toronto. Eductor, deep well and vacuum wellpoint systems are being used to lower the water levels by as much as 16 metres for the construction of the twin tunnels and associated structures. The design and performance of the dewatering systems will be described. Unanticipated difficulties and their solution will be presented.

Jan 1, 1999

By N. S. Keith

SOME time ago, a firm engaged largely in the manufacture of copper sulphate, applied to me for information as to the practicability of obtaining the copper from their mother liquors by means of electricity ; having reference, more especially, to obtaining the electric current from some magneto-electric or dynamo-electric machine. The mother liquors were the result of several solutions of commercial scrap copper, containing impurities, the quantity of which

Jan 1, 1878

By J. C. Lee

This investigation considers the penetration of a crack through an interfacial boundary separating two materials. The interface is assumed to be an imperfect bond characterized by frictional resistance and the cracks are assumed to be pressurized. The formulation is achieved through the use of complex variable methods together with the application of dislocation solutions. Results are given in the form of dimensionless variables that represent the injection of an incompressible liquid.

Jan 1, 1984

By J. Geisler

When addressing Germany’s resource supplies, we need to distinguish between those domestically available and imported ones. Resource extraction ostensibly competes with the designation of protection areas. However, the parallel existence of wildlife and plant life, and operations in the areas used for resource extractions is continually underestimated. The European Commission has compiled guidance documents facilitating the extraction of resources from protected areas. With regard to resource productivity, the market appears to be the appropriate instrument for minimising resource consumption. Policy makers are now called upon to create a legal framework leading to a consensus accepted by society.

Jan 1, 2011

By N. S. Keith

Some time ago, a firm engaged largely in the manufacture of copper sulphate, applied to me for information as to the practicability of obtaining the copper from their mother liquors by means of electricity ; having reference, more especially, to obtaining the electric current from some magneto-electric or dynamo-electric machine. The mother liquors were the result of several solutions of commercial scrap copper, containing impurities, the quantity of which

Jan 1, 1879

By C. W. A. Muir

Laboratory and plant-scale testwork on the extraction of gold from highly refractory antimonial and arsenical concentrates using both direct low-alkalinity pressure cyanidation, and acidic pressure pre-leaching followed by ambient low-alkalinity cyanidation, is described. A novel method for treating effluent solutions containing extremely high concentrations of base metal cyanides, as well as arsenic and antimony compounds, was developed in order to make the process ecologically acceptable.

Jan 1, 1984

By A. M. Gaudin

THIS paper presents, with the help of colored photomicrographs, the new method of mineral identification termed "selective iridescent filming." This method pertains to the field of determinative mineralogy, which it provides with tools for: (1) phase identification, (2) solid solution analysis. The method should be particularly useful in the applied fields of: (1) paragenesis of ore deposits, (2) mineral dressing, (3) mineral synthesis and study of phase equilibria.

Jan 1, 1938

By Damian R. Siebert

Risk-reduction measures implemented during the design and construction of a 21-story pile-supported building adjacent to a below-grade 100-year-old sewer structure were keys to a successful foundation system. Avoiding damage to the existing sewer structure during construction activities and the future ability to access the structure post-construction were the main concerns for the utility owner. Clear communication and a deliberate design process between all parties ? utility owner, building owner, structural engineer, geotechnical engineer, architect, and contractor ? were integral to the project?s success. This collaborative process helped all parties to understand the risks, both real and perceived, and to develop mitigation measures to reduce the risks. Bringing together all parties to engage in dialogue and encouraging open communication throughout the project were paramount to its success. By implementing the joint design plan, using mutually-acceptable construction techniques, and careful monitoring, the building foundation was successfully installed and all parties? risks were averted.

Jan 1, 2011

By Frederick Felder

The paper point out the Angostura deposit is located in Colombia. The Angostura deposit, located within the Eastern Cordillera of Colombia is hosted by Triassic-Jurassic quartz monzonite and quartz diorite porphyries emplaced into Precambrian gneisses of the Bucaramanga Group. Silicification, pyritization, sericitization, alunite and pyrophyllite and other alteration and indicator minerals suggest a high sulfidation origin for the strong hydrothermal alteration. Major faults and shear zones occur in the area with NE, E-NE, E-W, WNW, NW and N-S directions. Analysis of geological results and structural modeling has also demonstrated that there is potential for additional high-grade ore shoots within the presently known mineralized structures. Delineating these structures should result in an increase of overall grade and contained ounces.

Apr 22, 2003

By A. M. Gaudin

THIS paper presents, with the help of colored photomicrographs, the new method of mineral identification termed "selective iridescent filming." This method pertains to the field of determinative mineralogy, which it provides with tools for: (1) phase identification, (2) solid solution analysis. The method should be particularly useful in the applied fields of: (1) paragenesis of ore deposits, (2) mineral dressing, (3) mineral synthesis and study of phase equilibria.

Jan 1, 1938